#include <iostream>

int add(int a, int b);

int sub(int a, int b)
{
    return a - b;
}

int main()
{
    int a = 5, b = 7;
    std::cout << "a + b = " << add(a, b) << std::endl;
    std::cout << "a - b = " << sub(a, b) << std::endl;
    return 0;
}

int add(int a, int b)
{
    return a + b;
}
